Some ground robots exist that address an indoor surveillance mission. Specifically, Endeavor Robotics markets the 110 FirstLook as a small portable reconnaissance robot. See U.S. Pat. No. 7,926,598 incorporated herein by this reference. The robot incorporates a rear flipper that aids in stair climbing and obstacle traversal. However, the robot is small enough that it is easily stymied by large obstacles.
Larger robots readily climb stairs and traverse obstacles, but these robots are much larger (large enough to span several stairs). See U.S. Pat. Nos. 6,263,989; 8,201,649; and 8,602,134 incorporated herein by this reference. But, they may not be suitable for dismounted transport in a backpack, or operation within a confined environment that could include indoor situations, inside ships and aircraft, or inside manufacturing plants with closely spaced machinery.
As an alternative to ground robots, an exclusively aerial solution could be considered. A wide number of “quad-rotor” or multi-rotor drones are presently commercially available. However, these drones have several shortcomings for an indoor surveillance application. For example, quad-rotor drones often rely on GPS for knowledge of their position. GPS is typically not available indoors. It also is difficult to maneuver quad-rotors indoors without colliding with indoor obstacles, walls, and ceilings. Finally, a typical quad-rotor flight time is short, about 15 minutes.
Some drones have been designed with protection so that the can safely collide with indoor obstacles. Such a design is described in U.S. 2014/0131507 incorporated herein by this reference. However, the additional cage structure only exacerbates problems with short persistence by adding additional flying weight.
Hybrid vehicles that combine a quad-rotor with a wheeled or tracked vehicle also exist. Some examples are described at http://www.bgobeyond.co.uk. These vehicles can leverage their flight capability to surmount obstacles, yet can also function as ground robots. However, the large rotors required for lift span nearly the entire surface of the robot and the payload weight (and total weight, for that matter) seems low. See also U.S. Pat. No. 9,364,766 incorporated herein by this reference.